The present invention relates generally to the vehicle art and, more particularly, to a lifting apparatus pivotally mounted above the cab of a refuse collection vehicle.
In recent years, businesses and individuals have increasingly relied upon large refuse containers which can be lifted only by mechanical lift devices. The trucks used to transport refuse to a dumping location typically have fork lift-type devices to hoist the container above the vehicle body and tilt it so that the contents are emptied into the vehicle body. One such vehicle is described in U.S. Pat. No. 2,906,419 to Visco, which desribes a rear loading type of lift apparatus. The refuse container is engaged by a fork lift and hoisted above the body of the vehicle by a chain and sprocket drive device. When the container is above the body, it swings down under the force of gravity to dump its contents into the truck body.
Other refuse vehicles, such as that described in U.S. Pat. No. 3,140,788 to Clar, are of the front loading type. The Clar vehicle has a lift arm assembly pivotally mounted to the top front portion of the vehicle body at an elevated location behind the cab to support a fork lift engageable with a refuse container. The lift arm is hoisted above the body by hydraulic cylinders acting on the chassis behind the cab, and the container is inverted to dump its contents by hydraulic cylinders acting between the fork lift and the lift arm assembly.
Another front loading refuse vehicle is described in U.S. Pat. No. 3,207,345 to Ord, wherein a pair of side arms are pivotally mounted to the chassis behind the vehicle cab, a pair of hoist arms are pivotally mounted to outer ends of the side arms, and a fork arrangement is pivotally mounted to the hoist arms. Hydraulic rams mounted to the hoist arm and to the chassis behind the vehicle cab lift the hoist arms, fork arms and container above the vehicle cab. By utilizing a rotary actuator and gravitational forces, the container is rotated so that the contents of the container empty into the open receptacle of the truck body.
A front loading refuse truck having a pair of arcuate channels on each side is described in U.S. Pat. No. 3,282,453 to Wood. A fork-type loader arm is mounted to one pair of channels while tubular spacer elements extend between the loader arm and the second pair of channels. The channels extend between the truck body behind the cab and to the truck bumper, and the loader arm is driven upwardly toward the body by a pair of chain and sprocket mechanisms. The spacer element follows the secondary channel as the loader arm moves and acts to invert the container over the truck body at the appropriate time.
A similar refuse truck is disclosed in U.S. Pat. No. 3,174,636 to Dempster, in which two sets of channel rails are attached to the bumper and the body of the truck. The first channel rails extend vertically from the truck bumper, horizontally over the truck cab, and then downwardly at locations behind the cab. The second channel rails extend vertically from the truck bumper, horizontally below the first channel rails, and then diagonally upwardly to the top of the truck body. A fork apparatus having two sets of rollers are disposed between the first and the second channel rails. An endless chain and sprocket drive located within one of the first channel rails engages one set of rollers to move the fork apparatus along the rails. The relative positioning of the first and second sets of rails causes the fork apparatus to rotate to a position at which the contents of a container are emptied when the fork apparatus reaches the truck body.
The refuse truck most widely used is of the "A" frame type, in which a pair of unitary frames extend up and over the truck cab in a lowered position thereof to support a pair of fork arms in front of the cab. The frames are pivotally attached to the truck chassis or body at a location behind the cab and are acted upon by a pair of ram cylinders mounted to the chassis or body of the truck to pivot the frames upwardly and rearwardly over the cab. The fork arms engage a refuse container and are raised over the truck cab as the frame pivots to empty the contents of the container into the truck body.
The devices described above are usually very heavy, adding up to 3000 lbs to the weight of the vehicle. Because most cities and highway departments place upper limits on the total weight of heavy vehicles, the legal load carrying capacity of a refuse vehicle is reduced by the weight of its chassis and the lift device used. Additionally, most cities and highway departments regulate the width of trucks. This causes the bodies of refuse trucks incorporating "A" frame loading arms to be unduly limited since the hopper opening is located between the arms thereby limiting the width of the hopper opening.
Therefore, there is a current need for a refuse container lift apparatus which is simple, relatively light and does not substantially limit the width of the hopper opening, thereby increasing the load carrying capacity of the truck.